I can’t stop thinking about crocodiles for some reason so here’s some cool pictures I found of probably the second largest one in captivity, his name is Utan:
isn’t he beautiful
listen to the SOUND when he bites
and that’s not even a real power bite, that’s mostly just heavy bone falling on heavy bone from his jaws and the air rushing out from between them
2000 pounds of Good Boy
you get me
I honestly expected like 5 notes, what HAPPENED here
More tags on this ridiculous post:
Wait, thats the 2nd biggest crocodile? Then what does the biggest one look like?
That would be Cassius, a very old Saltwater crocodile who is estimated to be around 114 years old and lives at Marineland Melanesia in Green Island, Australia. His official measurement is 5.48 meters, which makes him the largest in captivity currently. Because Utan is only slightly smaller and much younger, (only in his 50s), he will likely break Cassius’ record eventually. But for now, Cassius holds the title:
He is NOT, however, either the largest crocodile ever captured in Australia OR the largest ever in captivity.
A slightly larger crocodile has been reported (though not yet comfirmed) to have been captured at 5.58 meters.
And while the famous Brutus of the Adelaide River was estimated to be just slightly larger than Cassius at 5.5m, he was driven out of his territory by a younger and even larger crocodile, who as a result has been given the name, The Dominator. He is estimated to be just over 6m.
This is Brutus, with an appropriate caption:
It is believed that he lost that arm in a fight with a Bull Shark.
The Bull Shark lost.
THIS is the crocodile who kicked him out. The Dominator:
And that’s STILL not the biggest.
The largest living crocodile ever reliably measured was Lolong, who for the 1.5 years between his capture and his death was the largest crocodile ever held in captivity, at a whopping 6.17 meters (20 feet 3 inches) and 1075 kg (2,370 lbs). He had been feeding on both humans and very large livestock in the Bunawan creek in Agusan del Sur in the Philippines. It took 100 people all night to drag him to shore during his capture.
And here’s why:
Also, to prevent credit from getting buried on a separate reblog, I have been informed that the above image of the crocodile with the cartoon eyes and halo was made by @rashkah! (And it is wonderful and I would like to thank him for its existence, because it perfectly captures my feelings about terrifying giant primordial reptiles.)
As far as Brutus is concerned I was led to believe that he lost that arm when relatively young.
Since then Brutus developed a habit of hunting and eating Bull Sharks.
Here’s him with a prey.
And if you thought that you’ll be safe if you just stay out of Australia then think again!
Meet Gustave the Nile Croc.
This crocodile became almost legendary for both it’s size and the habit of hunting both livestock AND humans.
So how big is Gustave?
No one is sure. Since he was NEVER captured.
His estimated size is of at least 5,5m but some give him over 6m.
The terrifying parts are:
1) He is still growing having only about 60 years.
2) Adult crocodiles often perform a gesture of submission to him – something usually done by young crocodiles toward adults – Gustave is just THAT BIG.
3) His sheer size makes it difficult for him to catch agile prey Nile crocs tend to feed on – hence why he developed a habit of hunting either larger prey like Hippopotamus or creatures which are not good at spotting danger in the first place like livestock and humans.
And this is NOT ALL.
Gustave actually has a noticeable scars on his body – he was shot at east 3 times and stabbed with a spear or something similar at one occasion.
He lived to tell the tale – my question is:
What happened to that one dude who attacked Gustave with a spear?
*Crocodile Dundee voice* Mate, that’s not Gustave:
THIS is Gustave:
And he is the PERFECT CROCODILE. He is the perfect example of what I mean when I talk about (as I do) how the morphology of extremely large crocodiles adapts to the changing physics of their bite.
This is a typical adult Nile Crocodile:
And THIS is a god among his kind:
This is it, folks. The Final Form. THIS is what peak performance looks like.
Crocodiles and physics have an interesting relationship. Crocodiles have, by a CONSIDERABLE MARGIN, the strongest bite of any animal on Earth. EVER. Scaled up estimates (based on Nile and Saltwater crocodiles) give the extinct Deinosuchus an estimated bite force MORE THAN DOUBLE the recently updated Tyrannosaurus bite estimates. Living crocodiles have bite forces measured in the range of 5000 pounds per square inch, for an individual around 15-16 feet. It is estimated that modern crocodiles in the range of 18-20 feet would have bit forces around 7-8000 psi or more.
That’s a problem.
Because a crocodile’s skull is only designed to handle so much pressure. Go beyond that limit and the force of impact when those jaws snap shut could literally shatter their own skulls.
But evolution has spent hundreds of millions of years perfecting crocodiles, so PHYSICS ISN’T GOING TO STOP THEM. What ends up happening in the skulls of these extremely large crocodiles is they will increase dramatically in mass to compensate for the increased forces. A crocodile’s skull is almost exclusively solid bone, with only minimal space for nasal passages, a surprisingly advanced brain, and some slightly porous looking framework that helps the bone distribute the force over a larger area. The effect is by far the most pronounced in Nile crocodiles, which most regularly feed on larger prey and need to make use of all that power.
Compare, 26 inch skull:
vs 29 inch skull:
Both of those are Nile crocodile skulls (or rather, replicas thereof).
And just for fun, here are the skulls of completely different (and very extinct species), Deinosuchus:
and Purussaurus:
The bigger the crocodile (within a given species), the more massive the skull needs to be to compensate for that UNBELIEVABLE bit pressure. This is one way to see from a distance whether you are looking at a normal sized crocodile:
and a truly extraordinary individual:
One of the things about Gustave that’s so impressive is how healthy his teeth look. A lot of large crocodiles, in their old age, have very worn down and often missing teeth. They do replace them many times over a lifetime, but when they get very old this slows down. Gustave, at least in every picture taken of him, had teeth that were in very good condition.
Even crocodiles much smaller than Gustave’s reported size (probably similar in size to Dominator or Lolong) tend to have smaller or more worn teeth:
than the pinnacle of his kind:
Lolong! It means Gramps or Grandpa, because he’s a relic of an ancient world where crocs more massive than he was walked the earth. His body is on display somewhere right now though I forgot where.
Every time I see this post there’s more crocodiles. It’s the gift that keeps on giving.
why do jellyfish only sting when theres physical contact
why doesnt the electricity just surge throughout the entire ocean
why dont jellyfish rule the world
Fun fact! Jellyfish don’t use electricity to sting you. Whenever they feel pressure against their tentacles, it causes its cells to rapidly send out these stingers into your skin that then release its venom. Like this:
They are called nematocysts. They are what make box jellies and other fun lil critters so dangerous, because without these wee little daggers, the venom would have no way to get into your skin.
And yet something as thin as nylon stockings or pantyhose is enough to protect you, they are so small.
So if you’re scared of jellyfish? Wear sexy sheer undergarments into the sea like the regal creature you are.
I’m going to reblog this again because that is some of the best advice I have ever gotten on this blog.
I do feel bad for plants in general. Like, I know they are often as vicious as animals in many ways, just slower. But, I mean, they just show up and they’re like, “I Think I Will Evolve To Eat The Sun And Also Make Oxygen And How Now Is All This.” And, like, everything fucking dies at first (totally not plants fault, btw. okay maybe it was but they didn’t mean to) but then new things evolve. And they’re like, “Fuck it, eating each other suuuucks. Let’s eat the plants which give us life.” And so we start doing that. And plants are all, “Oh Dear No, I Do Not Care At All For Being Eaten. I Will Make Myself Into Poison Sometimes.” But, y’know, stuff kept eating plants anyway so plants, ever the bro, came up with a new idea. “I Have Made A Decision About Being Eaten And You May Eat Me Friends And Here Is An Especially Tasty Bit Packed All Full of Delicious Sugars Which I Have Produced At Great Cost (What They Do Not Know Is That My Seeds Are Within And Shall Be Propagated Near And Far By Their Dung)“ But that’s not good enough for animals, no, not at all. We love the fuck out of some pomegranates but also alliums which are like, “I Have Not Decided To Go In For This Being Eaten Business. I Shall Be Very Foul Tasting And Also A Poison.” But no, sorry, onions, you fucked up. You accidentally wound up with a species that just doesn’t give up or fully comprehend the idea of things tasting “”‘bad’“’ or other concepts like not eating poison. (Sorry, plants, later we turn some of you who are not poison into a poison we consume recreationally. We really enjoy eating poison.) Legit, alliums are deadly to, like, every other species. And we call them aromatics and throw them in everything. Peppers are the best, though. They completely got on the being eaten train. BUT ONLY BIRDS Peppers are like, “You May Eat Me, Fair Avian, For You Are Sure To Spread Me A Great Distance. But, Mammal, Take HEED. Should You Eat Me Then I Will Burn You Most Terribly.” And we were all about that. “The FUCK, burning? I love pain,” said humans, presumably. “You know, peppers, you and evolution have done a good job at burning us but I am pretty sure we could make your chemical agony even more potent. Come hang with us,” humans added to a very confused pepper just before creating the ghost chili.
In 2010, the RIKEN institute in Japan created mutant cherry blossom trees by firing ion beams at them in a particle accelerator. The mutated trees now bloom four times a year and produce more flowers.
a wise use of science powers
ok so i’m not saying this is the most japanese thing ever, but I’m not saying it’s not
“we have a ray gun that creates mutants” anime level 8/10
“we used it to make super cherry blossoms” japan level 10/10
“so are they like firebreathing carnivorous flowers or” “no they just make more flowers, more often” aesthetic level 11/10
“well done, this is exactly what we hoped would happen when we paid a zillion dollars to build a particle accelerator” —the project backers
Particle physics is fucking magic
Some wizards took a magic box into the woods and fucked up some trees. I love this shit
“ok so should we mutate like a super army or-” “no. this sakura tree.” “but why” “hanami four times a year instead of once. imagine”
most vegetables are just different kinds of broccoli
Explain
broccoli, cabbage, kohlrabi, kale, brussel sprouts, collard greens, savoy, and cauliflower are all the same species of plant, Brassica oleracea
most veggies is the same
But wait, there’s more!
Brassical oleracea, cabbage and so on, hybridizes with B. rapa, turnip and Chinese cabbage, to make B. napus, rutabaga and rapeseed. It also hybridizes with B. nigra, black mustard, to form B. carinata, Ethiopian mustard. And B. rapa and B. nigra hybridize together to form B. juncea, Indian mustard.
Together these relationships make up the fantastic Triangle of U!
And why it it called the Triangle of U? Because of this awesome guy, botanist
Working in Japan in the 1930s and using his Japanized name of
U Nagaharu, he analyzed the evolutionary history of the six species through careful breeding techniques. “Woo made synthetic hybrids between the diploid and tetraploid species and examined how the chromosomes paired in the resulting triploids” (Wikipedia). This theory of hybrid origin, named the Triangle of U in his honor, has since been confirmed by genetic analysis.
If you set out to create every-which-way hybrids out of three congeneric species, and make sure that they were still all tasty, they would call you mad! Mad! But Woo proved that nature is even more of a mad scientist than a human could ever be.
So listen up y’all, nothing drives me crazier as both a writer and a scientist than seeing alien diseases that make no fuckin’ sense in a human body.
If you’re talking about alien diseases in a non-human character, you can ignore all this.
But as far as alien diseases in humans go, please remember:
DISEASE SYMPTOMS ARE AN IMMUNE RESPONSE.
Fever? A response to help your immune cells function faster and more efficiently to destroy invaders.
Sore/scratchy throat? An immune response. Diseases that latch onto the epithelium of the throat (the common cold, the flu) replicate there, and your body is like “uh no fuckin’ thanks” and starts to slough off those cells in order to stop the replication of new virus in its tracks. So when it feels like your throat is dying? guess what it literally is. And the white spots you see with more severe bacterial infections are pus accumulation, which is basically dead white blood cells, and the pus is a nice and disgusting way of getting that shit outta here.
(No one really knows why soreness and malaise happens, but some scientists guess that it’s a byproduct of immune response, and others suspect that it’s your body’s way of telling you to take it easy)
headache? usually sinus pressure (or dehydration, which isn’t an immune response but causes headaches by reducing blood volume and causing a general ruckus in your body, can be an unfortunate side effect of a fever) caused by mucous which is an immune response to flush that nasty viral shit outta your face.
Rashes? an inflammatory response. Your lymphocytes see a thing they don’t like and they’re like “hEY NOW” and release a bunch of chemicals that tell the cells that are supposed to kill it to come do that. Those chemicals cause inflammation, which causes redness, heat, and swelling. They itch because histamine is a bitch.
fatigue? your body is doing a lot–give it a break!
here is a fact:
during the Spanish 1918 Plague, a very strange age group succumbed to the illness. The very young and very old were fine, but people who were seemingly healthy and in the prime of life (young adults) did not survive. This is because that virus triggered an immune response called a cytokine storm, which basically killed everything in sight and caused horrific symptoms like tissue death, vasodilation and bleeding–basically a MASSIVE inflammatory response that lead to organ damage and death. Those with the strongest immune systems took the worst beating by their own immune responses, while those with weaker immune systems were fine.
So when you’re thinking of an alien disease, think through the immune response.
Where does this virus attack? Look up viruses that also attack there and understand what the immune system would do about it.
Understand symptoms that usually travel together–joint pain and fever, for example.
So please, please: no purple and green spotted diseases. No diseases that cause glamorous fainting spells and nothing else. No mystical eye-color/hair-color changing diseases. If you want these things to happen, use magic or some shit or alien physiology, but when it’s humans, it doesn’t make any fuckin’ sense.
This has been a rant and I apologize for that.
As a microbiologist, I think the main advice here is to take into account real diseases and conditions before you make up a fictional disease or condition.
Some bacteria have physical effects on the body that cause symptoms (EHEC varitype of E. coli ruptures cells at the site of infection, which is usually the large intestine, hence, you have bloody stools from it). If your alien or “made-up” bacteria or virus causes a certain symptom, find a real bacteria or virus that causes the same symptom. They need to behave in a similar fashion and have similar physical traits. Bacteria and viruses do not evolve functions because they’re cool. They evolve them because they’re useful.
There are also dietary issues, medications and chronic diseases that cause physical changes–copper toxicity can cause an orange ring around the iris, an eyelash lengthening “medicine” causes darkening and/or color change of the iris, hemochromatosis (sometimes known as “Bronze Diabetes”) causes darkening of the skin etc. If you want to use this sort of thing, again, find something real that causes it and work through things logically.
Play your cards right, do your research and you will have hordes of readers in the scientific and/or biological community cheering, screaming and crying because they love your work.
@biologyweeps, this feels up your speculative alley – anything to add?
Ohhh.
I’d like to add that the same goes for parasitic infections, more or less. If you want a certain trait for a diseases, cross reference with existing parasites to see what’s happening, and also make sure you check what happens if you put a parasite in a host it’s not meant for. We can sensibly assume that alien parasites that encounter a human would be ‘wtf’ and potentially cause complications that would never happen in the native species. Maybe in the native species it causes a cold like reaction at worst, but in a human the parasites may attempt to nest in a totally different tissue. Maybe that causes widespread tissue damage by the parasite itself as it tries to borrow in? Again, check existing cases to see what horrific things could happen.
While we’re on it, also check how your disease is communicated. One of the things that annoy me so much with zombie movies is that ‘biting’ is supposed to be a very effective way to spread it. It’s not. Anything that requires such intimate contact is actually kind of hard to communicate. Airborne things? Now there we are at potential ‘oh shit’ territory. So if you want your disease to sweep the country/planet/ship, pick something that’s easily communicable.
Also consider the incubation period. How long until someone shows symptoms? Are they already infectious to other people before showing symptoms or still after they stopped? As mentioned above, illness symptoms are in most part immune responses and the immune system needs time to get up and run. Give it that time.
And while we’re at it… there are symptoms that aren’t immune responses. For example the cramps that accompany tetanus are caused by a toxin the bacterium produces that damages/destroys nerve cells. Viruses can cause tissue damage when they insert in cells, replicate in there and destroy the cell on exit. Think of how HIV can wreak havoc on the human immune system by killing of a specific kind of cell. Depending on where your viruses likes to replicate it can massively impact the look of it. Something that destroys liver cells will look different (and if survived may come with different long term damage) than something that prefers skin or muscle cells. If it’s alien also consider how it might behave differently in its original host.
Fantastic post, I can relate to OP 100%. More points:
Nothing makes me groan harder than a made-up plague which gives anyone X diseases within seconds to MINUTES. I’m looking at you, most zombie movies. And if your alien/synthetic/sci-fi pathogen is at all like a virus (read: no metabolism of its own, just genetic material of some kind which it uses to reprogram host cells), then the rate at which it mupltiplies is limited to what normal human cells can do. Now, viruses can multiply pretty damn fast. But give you symptoms within MINUTES? Nope.
So long as we’re on the subject of epidemiology, and speed:
"Oh no, patient died less than a day after being infected! We’re all doomed!“ Wrong. While that SOUNDS scary, a plague that kills that quickly would not actually be that dangerous, and would be unlikely to have evolved to begin with. A disease needs to pass itself on to at least one other person, on average, before it kills its host, or it’s doomed to extinction. Any virus that kills its host before it has a decent chance of being passed on will basically quarantine itself. (Of course, you CAN do this if you handwave its origins as being made in a lab or whatever, just know it won’t realistically pose a truly terrifying threat on a population level.)
Mmore ideas for a realistically scary made-up plague:
– Long incubation period (say, a couple of weeks), making quarantine much more difficult, disruptive to everyday life, and unlikely to succeed.
– Infectious period != symptomatic period, i.e. someone can spread the disease before they appear sick. (Note: if this condition is met, then dying very rapidly after *manifesting symptoms* becomes plausible again, more plausible than dying quickly after being infected.)
– The possibility or relative prevalence of healthy carriers – think Typhoid Mary. I.e. rare people who skip the symptoms part entirely but are still infectious.
– The disease is transmitted through an animal that is hard to keep out, the definition of “hard to keep out” would depend on the setting here. Poor water sanitation means waterborne bacteria and microscopic parasites would be a huge danger. Insect or arachnid (e.g. tick) bites could be a danger in almost any setting..
– As an alternative to above point: the bacterial/viral/parasite/whatever can form spores that are fucking EVERYWHERE. (Read: the reason for both tetanus and botulinum poisoning.)
– The pathogen is both dangerous and impossible to fully exterminate through vaccination because it has a huge population of reservoir hosts. (Reservoir hosts are entire SPECIES that can carry and propagate the disease without being affected much by it.) Same way the Black Plague is still out there because a shitton of rodent species passively carry it.
And many more things if you do some research for inspiration! Pathogens are scary, fascinating things, and I really wish we had more realistic fictional representation of them than “virus which causes zombie behaviour in 3 seconds flat” (looking at you, 28 Days Later) and “virus which can MIND-CONTROL people who view the main carrier through a COMPUTER SCREEN” (wtf???) (looking at you, Jessica Jones).
Hollow trees are often more stable than before their cores rotted! “The removal of the tree’s dead heart brings yet another advantage. The change of form from solid pillar to hollow cylinder alters the way in which the trunk reacts to mechanical stress. It is much more resilient and stable. The removal of many tons of timber also reduces the strain on the tree’s elderly and doubtless somewhat decayed root system. The result is that an old hollow tree is often able to withstand a gale better than a younger undecayed one. In the ancient hunting parks of England such as Windsor, where trees stand out in the open, unprotected by others from the wind, it is by no means rare after a storm to discover that hollow oaks, four or five hundred years old, remain upright when younger ones, a quarter their age, have been blown over.” https://asknature.org/strategy/relationship-provides-nutrients-stability/
Suzanne Sadedin, Ph.D. in evolutionary biology from Monash University
I’m so glad you asked. Seriously. The answer to this question is one of the most illuminating and disturbing stories in human evolutionary biology, and almost nobody knows about it. And so, O my friends, gather close, and hear the extraordinary tale of:
HOW THE WOMAN GOT HER PERIOD
Contrary to popular belief, most mammals do not menstruate. In fact, it’s a feature exclusive to the higher primates and certain bats*. What’s more, modern women menstruate vastly more than any other animal. And it’s bloody stupid (sorry). A shameful waste of nutrients, disabling, and a dead giveaway to any nearby predators. To understand why we do it, you must first understand that you have been lied to, throughout your life, about the most intimate relationship you will ever experience: the mother-fetus bond.
Isn’t pregnancy beautiful? Look at any book about it. There’s the future mother, one hand resting gently on her belly. Her eyes misty with love and wonder. You sense she will do anything to nurture and protect this baby. And when you flip open the book, you read about more about this glorious symbiosis, the absolute altruism of female physiology designing a perfect environment for the growth of her child.
If you’ve actually been pregnant, you might know that the real story has some wrinkles. Those moments of sheer unadulterated altruism exist, but they’re interspersed with weeks or months of overwhelming nausea, exhaustion, crippling backache, incontinence, blood pressure issues and anxiety that you’ll be among the 15% of women who experience life-threatening complications.
From the perspective of most mammals, this is just crazy. Most mammals sail through pregnancy quite cheerfully, dodging predators and catching prey, even if they’re delivering litters of 12. So what makes us so special? The answer lies in our bizarre placenta. In most mammals, the placenta, which is part of the fetus, just interfaces with the surface of the mother’s blood vessels, allowing nutrients to cross to the little darling. Marsupials don’t even let their fetuses get to the blood: they merely secrete a sort of milk through the uterine wall. Only a few mammalian groups, including primates and mice, have evolved what is known as a “hemochorial” placenta, and ours is possibly the nastiest of all.
Inside the uterus we have a thick layer of endometrial tissue, which contains only tiny blood vessels. The endometrium seals off our main blood supply from the newly implanted embryo. The growing placenta literally burrows through this layer, rips into arterial walls and re-wires them to channel blood straight to the hungry embryo. It delves deep into the surrounding tissues, razes them and pumps the arteries full of hormones so they expand into the space created. It paralyzes these arteries so the mother cannot even constrict them.
What this means is that the growing fetus now has direct, unrestricted access to its mother’s blood supply. It can manufacture hormones and use them to manipulate her. It can, for instance, increase her blood sugar, dilate her arteries, and inflate her blood pressure to provide itself with more nutrients. And it does. Some fetal cells find their way through the placenta and into the mother’s bloodstream. They will grow in her blood and organs, and even in her brain, for the rest of her life, making her a genetic chimera**.
This might seem rather disrespectful. In fact, it’s sibling rivalry at its evolutionary best. You see, mother and fetus have quite distinct evolutionary interests. The mother ‘wants’ to dedicate approximately equal resources to all her surviving children, including possible future children, and none to those who will die. The fetus ‘wants’ to survive, and take as much as it can get. (The quotes are to indicate that this isn’t about what they consciously want, but about what evolution tends to optimize.)
There’s also a third player here – the father, whose interests align still less with the mother’s because her other offspring may not be his. Through a process called genomic imprinting, certain fetal genes inherited from the father can activate in the placenta. These genes ruthlessly promote the welfare of the offspring at the mother’s expense.
How did we come to acquire this ravenous hemochorial placenta which gives our fetuses and their fathers such unusual power? Whilst we can see some trend toward increasingly invasive placentae within primates, the full answer is lost in the mists of time. Uteri do not fossilize well.
The consequences, however, are clear. Normal mammalian pregnancy is a well-ordered affair because the mother is a despot. Her offspring live or die at her will; she controls their nutrient supply, and she can expel or reabsorb them any time. Human pregnancy, on the other hand, is run by committee – and not just any committee, but one whose members often have very different, competing interests and share only partial information. It’s a tug-of-war that not infrequently deteriorates to a tussle and, occasionally, to outright warfare. Many potentially lethal disorders, such as ectopic pregnancy, gestational diabetes, and pre-eclampsia can be traced to mis-steps in this intimate game.
What does all this have to do with menstruation? We’re getting there.
From a female perspective, pregnancy is always a huge investment. Even more so if her species has a hemochorial placenta. Once that placenta is in place, she not only loses full control of her own hormones, she also risks hemorrhage when it comes out. So it makes sense that females want to screen embryos very, very carefully. Going through pregnancy with a weak, inviable or even sub-par fetus isn’t worth it.
That’s where the endometrium comes in. You’ve probably read about how the endometrium is this snuggly, welcoming environment just waiting to enfold the delicate young embryo in its nurturing embrace. In fact, it’s quite the reverse. Researchers, bless their curious little hearts, have tried to implant embryos all over the bodies of mice. The single most difficult place for them to grow was – the endometrium.
Far from offering a nurturing embrace, the endometrium is a lethal testing-ground which only the toughest embryos survive. The longer the female can delay that placenta reaching her bloodstream, the longer she has to decide if she wants to dispose of this embryo without significant cost. The embryo, in contrast, wants to implant its placenta as quickly as possible, both to obtain access to its mother’s rich blood, and to increase her stake in its survival. For this reason, the endometrium got thicker and tougher – and the fetal placenta got correspondingly more aggressive.
But this development posed a further problem: what to do when the embryo died or was stuck half-alive in the uterus? The blood supply to the endometrial surface must be restricted, or the embryo would simply attach the placenta there. But restricting the blood supply makes the tissue weakly responsive to hormonal signals from the mother – and potentially more responsive to signals from nearby embryos, who naturally would like to persuade the endometrium to be more friendly. In addition, this makes it vulnerable to infection, especially when it already contains dead and dying tissues.
The solution, for higher primates, was to slough off the whole superficial endometrium – dying embryos and all – after every ovulation that didn’t result in a healthy pregnancy. It’s not exactly brilliant, but it works, and most importantly, it’s easily achieved by making some alterations to a chemical pathway normally used by the fetus during pregnancy. In other words, it’s just the kind of effect natural selection is renowned for: odd, hackish solutions that work to solve proximate problems. It’s not quite as bad as it seems, because in nature, women would experience periods quite rarely – probably no more than a few tens of times in their lives between lactational amenorrhea and pregnancies***.
We don’t really know how our hyper-aggressive placenta is linked to the other traits that combine to make humanity unique. But these traits did emerge together somehow, and that means in some sense the ancients were perhaps right. When we metaphorically ‘ate the fruit of knowledge’ – when we began our journey toward science and technology that would separate us from innocent animals and also lead to our peculiar sense of sexual morality – perhaps that was the same time the unique suffering of menstruation, pregnancy and childbirth was inflicted on women. All thanks to the evolution of the hemochorial placenta.
just moving along like everyone else 